Premoistened wipes for cleaning surfaces are known in the art. For example, U.S. Pat. No. 3,954,642 discloses a textile fibrous structure suitable for cleaning purposes and impregnated with surface active agents, in which the textile fibrous structures are built up from water-insoluble high polymers with a content of carboxyl groups able to form salts, which are present substantially as free carboxyl groups, and the impregnation consists of at least one nonionic surface-active agent from the group of water-soluble alkylene oxide derivatives. However, such textile fibrous structures, when subjected to pressure, quickly releases the composition incorporated therein, which reduces the overall area able to be cleaned by the wipe, due to the earlier premature release of the cleaning fluid. Therefore, when the composition is release too quickly from the substrate, the cleaning wipe is only able to clean relatively small areas before running out of cleaning solution.
Some developments have focused on providing a substrate for a premoistened wipe that will provide controlled release of fluid from the premoistened wipe. For example, U.S. Pat. No. 5,507,968 discloses a cleansing article that comprises a porous pad that includes a controlled detergent release composition comprising a polyacrylamide polymer and a detergent. The polyacrylamide polymer is a water swellable polymer. In use, the polyacrylamide polymer swells and slowly dissolves to provide a controlled release of the detergent incorporated therein. However, such polymers tend to cause filming and streaking problems, especially on hard surfaces.
U.S. Pat. No. 5,421,898 discloses an element for controlled release of a quaternary ammonium disinfectant in aqueous solution comprising a substrate coated with the residue of an aqueous composition of a certain water soluble polymer and a quaternary ammonium disinfectant. The water soluble polymer has a molecular weight of 85,000 to 186,000 and a degree of hydrolysis of 87 to 89 percent. The aqueous composition of the water soluble polymer and quat is applied to the substrate and dried, leaving a residue on the substrate. The water soluble polymer binds the quat to the substrate and releases the quat when the substrate is wetted. Thus, the wipe disclosed is a dry wipe, as opposed to a premoistened wipe.
Airlaid substrates have previously been utilized in premoistened wipes. Such airlaid substrates can exhibit some controlled fluid release properties. However, such substrates typically contain a binder material in order to bond the fibers of the substrate together. Binder materials can be undesireable because they can cause problems such as filming and streaking, especially on hard surfaces. Another potential problem with airlaid substrates that contain binders in premoistened wipes relates to the potential of the binder to decompose, depending on the liquid composition impregnated into the substrate, and thus cause the substrate to break apart over time.
It has therefore been desired to develop a substrate for a premoistened wipe that is capable of controlled fluid release, without having to utilize materials such as water swellable polymers and the like, while minimizing filming and streaking, especially on hard surfaces.